Propeller.



c. A. HARTFIEL.

PROPELLER.

APPLICATION FILED AUG. 5, 1914.

RENEWED MAR. 17,1916- Patent-ed Apr. 25,1916.

WITNESSES A TTOR/VEYS THE COLUMBIA PLANOGRAPH CL. WMHXNUTON, D. C-

barren smarts ra rnn r orries.

CHARLES A. HARTFIEL, OF NEW YORK, N. 35., ASSIGNOR OF FORTY ONE-HUNDREDTHS TO SOPHIA OLSI-IANSKA, OF YORK, N. Y.

PROPELLER.

Patented Apr. 25, 1916..

Application filed August 5, 1914, Serial No. 855,118. Renewed March 11.7, 1916. Serial No. 84,952.

To all whom it may concern:

Be it known that I, CHARLES A. HART- FIEL, a citizen of the United States, and a resident of the city of New York, borough of Brooklyn, in the county of Kings and State of New York, have invented a new and Improved Propeller, of which the following is a full, clear, and exact description.

This invention relates to marine propulsion, and has particular reference to a novel form of screw propeller for use upon ships or boats of any desired type.

Among the objects of the invention, therefore, is to so improve the form or design of a screw propeller as to make it more efficient or to produce a more satisfactory result as to power and speed in proportion to the amount of power expended than propellers now in common use.

The foregoing and other objects of the invention will hereinafter be more fully described and claimed and illustrated in the drawings forming a part of this specification in which like characters of reference indicate corresponding parts in all the views, and in which Figure l is a side elevation, partly broken away, indicating a preferred form of the invention; Fig. 2 is a front elevation looking towardthe left in Fig. 1; and Fig. 3 1s a diagram indicating the comparative forms in radial lines of the different parts of the propeller blade, the several parts shown in this diagram being taken on the correspond ing radial lines of Fig. 2 and lettered accordingly.

A propeller screw made. in accordance with the disclosure herein may be of any suitable material, either sheet metal, cast metal, or any other material which may be found suitable for the particular purpose for which the propeller may be designed, and while I show one preferred form of the invention I wish it to be understood that the precise shape or configuration indicated may be departed from within certain l1m1ts without avoiding the spirit of the invention or sacrificing any of its advantages.

Referring more particularly to the drawings I show at a sleeve or shaft of any suitable size or construction adapting the propeller to be secured in position for practical use with the engine or power shaft.

The blade 11 constituting the principal part of the invention is in the nature of a spiral screw but of peculiar form as applied to the shaft or hub 10. This blade for the purpose of explanation of its form and manner of construction, may be regarded as cut from a circular disk of flat material havmg a circular hole in the center of a diameter somewhatvlarger than the exterior diameter of the shaft 10. Said disk is slitted radially so as to form the front and rear edges 12 and 13 respectively. WVhen applied to the shaft as illustrated and the two radial edges 12 and 18 spread apart longitudinally of the shaft, the central hole will snugly conform to the surface of the shaft and assume substantially a true spiral indicated at 14. Any suitable means may be provided for securing the blade to the shaft along the line 14 just described when these parts are made separate. I wish it to be dis tinctly understood, however, that the foregoing description referring to sheet metal is to be taken merely as a means of describing the form of the blade when finished and not as a means for making the device.

The blade necessarily is made of rigid stiff material and maintains the form given to it. As shown best in Fig. l, the front portion'or lobe 15 of the blade is concavo-convex, the convexity being forward, and while the main portion of the lobe is inclined forwardly, forming an acute angle 16 with the axis of the shaft, the point 15 of the lobe is turned rearwardly with respect to the main portion thereof or substantially perpendicular to' the axis of the shaft. The rear end or lobe 17 of the propeller likewise is concavoconvex in form and the convexity of this lobe also is toward the front. The point 17 of the rear lobe, however, because of the combined effects of the rearward inclination of the lobe forming the angle 18 with the shaft .and the 'concavoconvex form of the lobe, is much farther from the median trans verse plane intersecting the shaft and the middle portion 19 of the blade than is the point 15 of the front lobe. It is to be noted also that the point 17 is spaced from the axis of the shaft at a less distance than the point 15 because of the circumstances just referred to, having reference to the inclination and the curved features.

The middle portion 19 of the blade or that portion represented by the line e of Figs. 2 and 3 is a true radiusof the circle and perpendicular to the axis of the shaft. The length of this radius is slightly greater than the distance between the point 15 and the axis of the shaft. In other Words, while each of the lobes is concaved on its rear face, forming in effect a shallow cup, the concavityof each merges gradually and substantially uniformly into the straight or fiat radial portion 19 of the blade.

I found by numerous careful experiments that this form of propeller possesses many advantages, over the forms of propellers.

now commonly in use.-- A propeller made as indicated, when substituted for a common propeller on the same vessel and using the same power, causes the vessel to be propelled at a much higher rate of speed than before the substitution is made. The front edge 12 of the lobe 15, the parts moving in the direction indicated by the large arrows on the drawings, cuts into and through the water and the lobe '15 tends to compress the water entering it because of the concavity in its rear face, such compression being maintained While the screw progresses through the water until the straight portion 19 is reached. The straight portion 19, however, being wider than the cupped portions, maintains its share of engagement with the water. The lobe 17, because of the combined inclination and rearward curve of the edge 13, has a sort of beating effect upon the water as the propeller spins around its axis, and hence the propeller is given a forward impulse or kick due to such beating action.

Having thus described my invention, I

claim as new and desire to secure by Letters Patent 1. In a propeller, the combination of a hub having a longitudinal axis and a blade surrounding the hub, said blade being of a spiral form and having its front and rear ends of concavo-convex form, the concavities of both being arranged in the same direction and on the same side of the axis aforesaid and the intermediate portion of the blade being flat.

2. In a screw propeller, the combination of a hub having a longitudinal axis and a blade secured to the hub and extending around the axis spirally, the front and rear ends of the blade being concave on their rear faces, and the middle portion of the blade being fiat and substantially perpendicular to said axis.

3. The herein described screw propeller comprising a spiral blade extending around a longitudinal axis, the front end of the blade being concave on its rear face, the rear end of the blade having its point spaced radially from the axis of the shaft at a less distance than the point of the front end of the blade, and the portion of the blade between the ends being on a greater radius than the point of the front end of the blade, a portion of the blade between said ends being substantially flat.

4. In a screw propeller, the combination of a hub having a longitudinal axis and a blade extending around the hub in a spiral direction, the front and rear ends of the blade extending outwardly from the axis at substantially the same angles but having their points both turned rearwardly with respect to the main portions of said ends and said angles, the point of the rear end being at a less radial distance from the axis of the hub than the point of the front end of the blade, and the middle portion of the blade being straight and substantially perpendicular to the axis, substantially as set forth. v

5. In a screw propeller, the combination of a shaft and a spiral blade extending therearound, the ends of the blade lying on the same side of the shaft, one end of the blade extending forwardly forming an acute angle with said shaft and curved thence rearwardly at its point, and the other end of the blade extending rearwardly forming an acute angle with the shaft and extending thence rearwardly at its point, said acute angles being substantially equal.

6. In a screw propeller, the combination of a shaft and a blade extending spirally therearound, the ends of the spiral forming acute angles with the shaft, one angle extending forwardly and the other rearwardly, each of said ends being concave on its rear face and a portion of the blade between said ends being fiat.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES A. HARTFIEL. Witnesses:

Geo. L. BEELER, SOPHIA OLSHANSKA.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patent:, Washington, D. O." 

